Comment 8 for bug 1988055

I was able to verify this with the following commands:

# lxc launch images:ubuntu/jammy test-unbound
# lxc exec test-unbound bash

# cat <<EOF >/etc/apt/sources.list.d/ubuntu-$(lsb_release -cs)-proposed.list
# Enable Ubuntu proposed archive
deb http://archive.ubuntu.com/ubuntu/ $(lsb_release -cs)-proposed restricted main multiverse universe
EOF

# apt update && apt dist-upgrade -y
# apt install unbound -y

# echo "
server:
  interface: lo" >> /etc/unbound/unbound.conf

# unbound-checkconf

unbound-checkconf: no errors in /etc/unbound/unbound.conf